**3. Factors affecting global food security**

Overpopulation, climate change, and urbanization are three worldwide concerns that have an impact on food security. Hunger and disease are most prevalent in areas of the world with the largest birth rates and population, where demand typically exceeds supply. Local ecosystems provide resources for food production, health, environmental management, and water to the people. The local ecosystem has a limited carrying capacity, and when this capacity is surpassed, the ecosystem comes under stress and starts to break down. This condition has been termed as ecosystem vulnerability [21]. Such vulnerable condition of the ecosystem can give to overfarmed soils, denuded grazing lands and dried up or contaminated wells.

Climate change is affecting various regions of the world. Climate change can affect food security and hence human health in a variety of ways [22, 23]. One important route is through climate change affecting the amount of food produced, both directly and indirectly through implications on water availability and quality, pests and diseases, and pollination services. Another way involves altering CO2 levels in the atmosphere, which has an impact on biomass and nutritional quality. Climate change can worsen food safety issues during transportation and storage. Limited food sources lead to nutritional deficiencies and these deficiencies can cause immune suppression and make the population more prone to illness [24]. Diseases lead to a greater demand on the body's energy reserves and necessitates the consumption of nutrients that aren't readily available. This is a cycle of hunger and disease that shortens one's life, decreases productivity, and limits one's potential.

Furthermore, due to the agricultural workforce's exposure to high temperatures, the direct effects of altering weather might have an influence on human health. There is the possibility for interactions with food availability due to changes in metabolic needs and physiological stress for persons exposed to severe temperatures; people may require more food to cope while simultaneously being unable to produce it [22]. All of these elements have the potential to affect both physical and cultural health by affecting the amount and quality of food available to people.

Food insecurity is aggravated by urbanization. Megacities, defined as cities with populations of 10 million or more, are particularly frequent in developing nations. In fact, low- and middle-income nations account for three-quarters of urban residents. The global economy has benefited from these nations' low-cost labour, which has fueled rural-to-urban migration. The majority of manufacturing jobs are in cities, and when overcrowded and depleted lands fail to provide basic economic requirements despite their ability to generate sufficient food, people migrate to these urban jobs and opportunities. Until now, rural farmers have been able to keep up with demand, but urban people' economic access to food remains a concern. The demand to feed these megacities, as well as the difficulties linked with economic food access, is enormous. This was seen in the years 2007 and 2008, when rising oil costs made food expensive for city residents all across the world [25].

Food security is not only about humans and their environment; it also involves animals, who are a key source of food for humans. As a result, under this situation, we cannot neglect infectious animal illness. Contagious animal illnesses can wipe out an animal population or drastically impair its productivity, which has an impact on food supply and access. Even if humans are not afflicted, the illness frequently has a significant impact on them. Any loss of animals means a loss of protein in the form of milk, meat, or blood, as well as a supply of labour to plow fields and deliver food to markets. Even illnesses with a low case-fatality rate but a high morbidity rate, such as foot and mouth disease, produce such severe sickness in the animal that its productivity is severely diminished. This can influence the food supply. Avian influenza, especially H5N1, decimated flocks across the Western Pacific, posing a

*Revolutionizing Integrated Pest Management Using Nanobiotechnology: A Novel Approach… DOI: http://dx.doi.org/10.5772/intechopen.101155*

food security issue [26]. Furthermore, zoonotic illnesses put people at danger when they ingest these animals, which happens often even when the animal is unwell. In terms of access and availability, food instability may push communities to seek alternative food sources, such as bush meat, thus exposing them to additional illnesses. This has been the case with illnesses such as sudden acute respiratory syndrome, acquired immunodeficiency syndrome (AIDS), and others [27].

Agriculture is directly or indirectly linked to the livelihood of a large percentage of the population in the developing countries. In recent years, agricultural productivity growth has slowed. Land is a limited resource, and many emerging nations are unable to expand their farmed areas [28, 29]. As a result, increasing agricultural production may be the only way to fulfill future food demand for a growing population. Because cultivable fertile land and related inputs are limited in most areas of the world, a new strategy to increasing future agricultural productivity development in most regions of the world may be intense agricultural expansion rather than widespread growth. As a result, diversification coupled with intensification of production and improving the resource utilization are important essential measures [30]. The disparity between feasible and actual yields for most crops implies a huge opportunity to boost food and agricultural output by increasing productivity [31]. According to the Food and Agriculture Organization, UN (FAO), in the developing world, around 80% of the growth in food production will have to come from increased yields and cropping intensity, with just 20% coming from arable land expansion [32]. As a result, intensification is critical not just to satisfy the growing demand for food grains, but also to reduce deforestation, environmental devastation, and global warming.
